1. Field of the Invention
This invention relates to a separator of the gyratory type and, in particular, to a separator in which motion is imparted to one or an assembly of pan screens to separate pulverulent or fibrous materials according to particle size or for separating particulate materials from a liquid suspension.
2. Description of the Prior Art
Various constructions have been proposed for gyratory devices used for effecting separation of particles. Generally, such separators have comprised an assembly of one or more of pan screens that are resiliently suspended on a support base and are driven by a gyration generator. As presently constructed, these devices are subject to a number of design limitations which result in frequent mechanical failure and maintenance. Commonly, the assembly of pan screens is supported on the frame or base by a plurality of circumferential compression springs that extend vertically between the lower extremity of the assembly and the supporting base. This construction tends to accentuate the side loadings, resulting in sagging and instability of the assembly and premature spring failure.
The individual screens of the pan screens must commonly be axially stressed to prevent screen slapping or undesired vertical vibration of the screen. This is performed by axially deflecting the center of the screen to provide a conical, rather than horizontal, screen. This method prevents use of a simple screen sweep and, furthermore, unnecessarily complicates and stresses the screen structure.
A design limitation in prior devices uses eccentric weights driven directly by an electric motor whose substantial mass is added to the mass of the sprung vibrating assembly, requiring higher eccentric forces and resultant higher bearing loads for an equal vibration amplitude.
Some systems have provided for screen deblinding and cleaning by placing balls or rings on the screens to impart a cleaning motion. These systems are not entirely satisfactory because they impart localized screen stresses by impacts of resilient balls or encounter jamming of the sliding elements.